The present invention relates to a method of controlling a power steering device, which controls a steering power of a vehicle in accordance with a vehicle speed and a steering angle.
In general, a steering power of a vehicle is high when the vehicle speed is low and decreases as the vehicle speed increases. For this reason, conventionally, a power steering device is hydraulically controlled such that an oil pressure is controlled in accordance with the vehicle speed and steering angle as shown in FIG. 4. Thus, a uniform steering response is obtained throughout the entire driving range. That is, according to a power steering device wherein an output is increased as a current supplied to a solenoid valve is increased, when the vehicle speed is low, a large current is supplied to the solenoid, and when the vehicle speed is increased and the steering angle is increased, the current supplied to the solenoid is decreased.
According to such a conventional method, no problem is posed under normal driving conditions. However, a reaction force from the tires is increased as the steering angle is increased. This poses a problem of a so-called "wall feeling" phenomenon. In this phenomenon, the steering force or resistance experienced by a driver is abruptly increased over a given steering angle.